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-rw-r--r--fs/cramfs/Kconfig30
-rw-r--r--fs/cramfs/inode.c212
2 files changed, 199 insertions, 43 deletions
diff --git a/fs/cramfs/Kconfig b/fs/cramfs/Kconfig
index 11b29d491b7c..ef86b06bc064 100644
--- a/fs/cramfs/Kconfig
+++ b/fs/cramfs/Kconfig
@@ -1,6 +1,5 @@
config CRAMFS
tristate "Compressed ROM file system support (cramfs) (OBSOLETE)"
- depends on BLOCK
select ZLIB_INFLATE
help
Saying Y here includes support for CramFs (Compressed ROM File
@@ -20,3 +19,32 @@ config CRAMFS
in terms of performance and features.
If unsure, say N.
+
+config CRAMFS_BLOCKDEV
+ bool "Support CramFs image over a regular block device" if EXPERT
+ depends on CRAMFS && BLOCK
+ default y
+ help
+ This option allows the CramFs driver to load data from a regular
+ block device such a disk partition or a ramdisk.
+
+config CRAMFS_MTD
+ bool "Support CramFs image directly mapped in physical memory"
+ depends on CRAMFS && MTD
+ default y if !CRAMFS_BLOCKDEV
+ help
+ This option allows the CramFs driver to load data directly from
+ a linear adressed memory range (usually non volatile memory
+ like flash) instead of going through the block device layer.
+ This saves some memory since no intermediate buffering is
+ necessary.
+
+ The location of the CramFs image is determined by a
+ MTD device capable of direct memory mapping e.g. from
+ the 'physmap' map driver or a resulting MTD partition.
+ For example, this would mount the cramfs image stored in
+ the MTD partition named "xip_fs" on the /mnt mountpoint:
+
+ mount -t cramfs mtd:xip_fs /mnt
+
+ If unsure, say N.
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index 7919967488cb..bcdccb7a820b 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -19,6 +19,8 @@
#include <linux/init.h>
#include <linux/string.h>
#include <linux/blkdev.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/super.h>
#include <linux/slab.h>
#include <linux/vfs.h>
#include <linux/mutex.h>
@@ -36,6 +38,9 @@ struct cramfs_sb_info {
unsigned long blocks;
unsigned long files;
unsigned long flags;
+ void *linear_virt_addr;
+ resource_size_t linear_phys_addr;
+ size_t mtd_point_size;
};
static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
@@ -140,6 +145,9 @@ static struct inode *get_cramfs_inode(struct super_block *sb,
* BLKS_PER_BUF*PAGE_SIZE, so that the caller doesn't need to
* worry about end-of-buffer issues even when decompressing a full
* page cache.
+ *
+ * Note: This is all optimized away at compile time when
+ * CONFIG_CRAMFS_BLOCKDEV=n.
*/
#define READ_BUFFERS (2)
/* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */
@@ -160,10 +168,10 @@ static struct super_block *buffer_dev[READ_BUFFERS];
static int next_buffer;
/*
- * Returns a pointer to a buffer containing at least LEN bytes of
- * filesystem starting at byte offset OFFSET into the filesystem.
+ * Populate our block cache and return a pointer to it.
*/
-static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned int len)
+static void *cramfs_blkdev_read(struct super_block *sb, unsigned int offset,
+ unsigned int len)
{
struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
struct page *pages[BLKS_PER_BUF];
@@ -239,11 +247,49 @@ static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned i
return read_buffers[buffer] + offset;
}
+/*
+ * Return a pointer to the linearly addressed cramfs image in memory.
+ */
+static void *cramfs_direct_read(struct super_block *sb, unsigned int offset,
+ unsigned int len)
+{
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
+
+ if (!len)
+ return NULL;
+ if (len > sbi->size || offset > sbi->size - len)
+ return page_address(ZERO_PAGE(0));
+ return sbi->linear_virt_addr + offset;
+}
+
+/*
+ * Returns a pointer to a buffer containing at least LEN bytes of
+ * filesystem starting at byte offset OFFSET into the filesystem.
+ */
+static void *cramfs_read(struct super_block *sb, unsigned int offset,
+ unsigned int len)
+{
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
+
+ if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sbi->linear_virt_addr)
+ return cramfs_direct_read(sb, offset, len);
+ else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
+ return cramfs_blkdev_read(sb, offset, len);
+ else
+ return NULL;
+}
+
static void cramfs_kill_sb(struct super_block *sb)
{
struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
- kill_block_super(sb);
+ if (IS_ENABLED(CCONFIG_CRAMFS_MTD) && sb->s_mtd) {
+ if (sbi && sbi->mtd_point_size)
+ mtd_unpoint(sb->s_mtd, 0, sbi->mtd_point_size);
+ kill_mtd_super(sb);
+ } else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV) && sb->s_bdev) {
+ kill_block_super(sb);
+ }
kfree(sbi);
}
@@ -254,34 +300,24 @@ static int cramfs_remount(struct super_block *sb, int *flags, char *data)
return 0;
}
-static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
+static int cramfs_read_super(struct super_block *sb,
+ struct cramfs_super *super, int silent)
{
- int i;
- struct cramfs_super super;
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
unsigned long root_offset;
- struct cramfs_sb_info *sbi;
- struct inode *root;
-
- sb->s_flags |= MS_RDONLY;
-
- sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
- if (!sbi)
- return -ENOMEM;
- sb->s_fs_info = sbi;
- /* Invalidate the read buffers on mount: think disk change.. */
- mutex_lock(&read_mutex);
- for (i = 0; i < READ_BUFFERS; i++)
- buffer_blocknr[i] = -1;
+ /* We don't know the real size yet */
+ sbi->size = PAGE_SIZE;
/* Read the first block and get the superblock from it */
- memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super));
+ mutex_lock(&read_mutex);
+ memcpy(super, cramfs_read(sb, 0, sizeof(*super)), sizeof(*super));
mutex_unlock(&read_mutex);
/* Do sanity checks on the superblock */
- if (super.magic != CRAMFS_MAGIC) {
+ if (super->magic != CRAMFS_MAGIC) {
/* check for wrong endianness */
- if (super.magic == CRAMFS_MAGIC_WEND) {
+ if (super->magic == CRAMFS_MAGIC_WEND) {
if (!silent)
pr_err("wrong endianness\n");
return -EINVAL;
@@ -289,10 +325,12 @@ static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
/* check at 512 byte offset */
mutex_lock(&read_mutex);
- memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super));
+ memcpy(super,
+ cramfs_read(sb, 512, sizeof(*super)),
+ sizeof(*super));
mutex_unlock(&read_mutex);
- if (super.magic != CRAMFS_MAGIC) {
- if (super.magic == CRAMFS_MAGIC_WEND && !silent)
+ if (super->magic != CRAMFS_MAGIC) {
+ if (super->magic == CRAMFS_MAGIC_WEND && !silent)
pr_err("wrong endianness\n");
else if (!silent)
pr_err("wrong magic\n");
@@ -301,34 +339,34 @@ static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
}
/* get feature flags first */
- if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
+ if (super->flags & ~CRAMFS_SUPPORTED_FLAGS) {
pr_err("unsupported filesystem features\n");
return -EINVAL;
}
/* Check that the root inode is in a sane state */
- if (!S_ISDIR(super.root.mode)) {
+ if (!S_ISDIR(super->root.mode)) {
pr_err("root is not a directory\n");
return -EINVAL;
}
/* correct strange, hard-coded permissions of mkcramfs */
- super.root.mode |= (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
+ super->root.mode |= 0555;
- root_offset = super.root.offset << 2;
- if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) {
- sbi->size = super.size;
- sbi->blocks = super.fsid.blocks;
- sbi->files = super.fsid.files;
+ root_offset = super->root.offset << 2;
+ if (super->flags & CRAMFS_FLAG_FSID_VERSION_2) {
+ sbi->size = super->size;
+ sbi->blocks = super->fsid.blocks;
+ sbi->files = super->fsid.files;
} else {
sbi->size = 1<<28;
sbi->blocks = 0;
sbi->files = 0;
}
- sbi->magic = super.magic;
- sbi->flags = super.flags;
+ sbi->magic = super->magic;
+ sbi->flags = super->flags;
if (root_offset == 0)
pr_info("empty filesystem");
- else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
+ else if (!(super->flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
((root_offset != sizeof(struct cramfs_super)) &&
(root_offset != 512 + sizeof(struct cramfs_super))))
{
@@ -336,9 +374,18 @@ static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
return -EINVAL;
}
+ return 0;
+}
+
+static int cramfs_finalize_super(struct super_block *sb,
+ struct cramfs_inode *cramfs_root)
+{
+ struct inode *root;
+
/* Set it all up.. */
+ sb->s_flags |= MS_RDONLY;
sb->s_op = &cramfs_ops;
- root = get_cramfs_inode(sb, &super.root, 0);
+ root = get_cramfs_inode(sb, cramfs_root, 0);
if (IS_ERR(root))
return PTR_ERR(root);
sb->s_root = d_make_root(root);
@@ -347,10 +394,79 @@ static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
return 0;
}
+static int cramfs_blkdev_fill_super(struct super_block *sb, void *data,
+ int silent)
+{
+ struct cramfs_sb_info *sbi;
+ struct cramfs_super super;
+ int i, err;
+
+ sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
+ sb->s_fs_info = sbi;
+
+ /* Invalidate the read buffers on mount: think disk change.. */
+ for (i = 0; i < READ_BUFFERS; i++)
+ buffer_blocknr[i] = -1;
+
+ err = cramfs_read_super(sb, &super, silent);
+ if (err)
+ return err;
+ return cramfs_finalize_super(sb, &super.root);
+}
+
+static int cramfs_mtd_fill_super(struct super_block *sb, void *data,
+ int silent)
+{
+ struct cramfs_sb_info *sbi;
+ struct cramfs_super super;
+ int err;
+
+ sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
+ sb->s_fs_info = sbi;
+
+ /* Map only one page for now. Will remap it when fs size is known. */
+ err = mtd_point(sb->s_mtd, 0, PAGE_SIZE, &sbi->mtd_point_size,
+ &sbi->linear_virt_addr, &sbi->linear_phys_addr);
+ if (err || sbi->mtd_point_size != PAGE_SIZE) {
+ pr_err("unable to get direct memory access to mtd:%s\n",
+ sb->s_mtd->name);
+ return err ? : -ENODATA;
+ }
+
+ pr_info("checking physical address %pap for linear cramfs image\n",
+ &sbi->linear_phys_addr);
+ err = cramfs_read_super(sb, &super, silent);
+ if (err)
+ return err;
+
+ /* Remap the whole filesystem now */
+ pr_info("linear cramfs image on mtd:%s appears to be %lu KB in size\n",
+ sb->s_mtd->name, sbi->size/1024);
+ mtd_unpoint(sb->s_mtd, 0, PAGE_SIZE);
+ err = mtd_point(sb->s_mtd, 0, sbi->size, &sbi->mtd_point_size,
+ &sbi->linear_virt_addr, &sbi->linear_phys_addr);
+ if (err || sbi->mtd_point_size != sbi->size) {
+ pr_err("unable to get direct memory access to mtd:%s\n",
+ sb->s_mtd->name);
+ return err ? : -ENODATA;
+ }
+
+ return cramfs_finalize_super(sb, &super.root);
+}
+
static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
- u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+ u64 id = 0;
+
+ if (sb->s_bdev)
+ id = huge_encode_dev(sb->s_bdev->bd_dev);
+ else if (sb->s_dev)
+ id = huge_encode_dev(sb->s_dev);
buf->f_type = CRAMFS_MAGIC;
buf->f_bsize = PAGE_SIZE;
@@ -573,10 +689,22 @@ static const struct super_operations cramfs_ops = {
.statfs = cramfs_statfs,
};
-static struct dentry *cramfs_mount(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data)
+static struct dentry *cramfs_mount(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data)
{
- return mount_bdev(fs_type, flags, dev_name, data, cramfs_fill_super);
+ struct dentry *ret = ERR_PTR(-ENOPROTOOPT);
+
+ if (IS_ENABLED(CONFIG_CRAMFS_MTD)) {
+ ret = mount_mtd(fs_type, flags, dev_name, data,
+ cramfs_mtd_fill_super);
+ if (!IS_ERR(ret))
+ return ret;
+ }
+ if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV)) {
+ ret = mount_bdev(fs_type, flags, dev_name, data,
+ cramfs_blkdev_fill_super);
+ }
+ return ret;
}
static struct file_system_type cramfs_fs_type = {
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-11 08:34:48 +0000